Q: Can i use a tune from my music library as a ringtone or message tone and if so ,how do i do it

Yes you can by using computer iTunes.

Here's a step by step tutorial:

1. Select a title (.mp3 or .m4a) in your iTunes Library

2. Do File > Get Info on selected title (Windows do Edit > Get Info)

3. In the dialog choose Options tab

4. Set Start Time and End Time (no more than 35 secs otherwise won't work)

5. Close dialog.

6. Now control click the title (right click) and choose Create AAC Version

7. When it is done, drag the newly create title to the desktop.

8. Delete the newly create title in iTunes.

9. Rename the title on your desktop from ringtone.m4a to ringtone.m4r

10. Drag and drop it into iTunes

Now you have a ringtone.

Make sure it is selected in iTunes for syncing with your new iPhone.

Exactly what does "Do file >" mean?

More questions...

When I click on ">" after the tune title there is no "get info" nor is there an "options" or "dialog"  tab.

Do File > Get Info on selected title (Windows do Edit > Get Info)

What this means is press   FILE then  press  GET INFO            in Windows click EDIT then click GET INFO

Thanks for the quick reply. I did everything you said, up to and incldsing creating the tune on the desktop and dragging it to the itune library, but it does not appear when I click the 'tone' tab. That file is empty. This is the same problem I have been having all along. I know I must be doing something wrong but cannot figure out what that is...

Gues what? I did what you said and it is now listed under tones! Now my problem is that I do not see a sync option so it does not appear as a tone choice on my iphone.

You have to connect (with dock cable) and select your iPhone (left Sidebar) in computer iTunes, in Tones tab, make sure "Sync Tones" and "All tones" are selected. At bottom right click Sync button.